Aspects of membrane function and assembly will be studied in Staphylococcus aureus, Spirillum itersonii and Paracoccus denitrificans. Major attention is given to the cytoplasmic and membrane associated nitrate reductase systems in these organisms. The role of b and c-type cytochromes in the formation and function of nitrate reductase will be studied with wild type and mutant strains of the organisms. BIBLIOGRAPHIC REFERENCE: Burke, K.A., and Lascelles, J. Nitrate reductase activity in heme-deficient mutants of Staphylococcus aureus. J. Bacteriol. 126:225-231 (1976).